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The moment magnitude scale (MW) provides an estimate of the total energy released in an earthquake and is currently the preferred magnitude scale in use by seismologists .
It is calculated from the seismic moment (M0 - which has the unit of dynes/cm =where 1 dyne/cm = 1x10-7 N/m) which is a measure of the total energy released during an earthquake and is derived based on the elastic moduli of the crust where the earthquake occurred, the length of the slip surface and the cross sectional area of the slip surface as follows:
M0 = G x AFx DF
Where:
G = Shear modulus of the rock mass
AF = Area of the rupture along the fault
DF = average displacement on AF
In order to make the moment magnitude scale (Mw) consistent with older magnitude scales such as the Local Moment (or "Richter") scale the seismic moment (M0) is converted into a logarithmic scale using the following equation:
Mw = 2/3 x log10 x (M0) - 10.7
This ultimately yields a dimensionless number and as such, Moment Magnitude has no units.
Please see the related question.
Wiki User
∙ 14y ago
Wiki User
∙ 14y agoBy using the Richter scale which is a logarithmic scale used to express the total amount of energy released by an earthquake. Its values typically fall between 0 and 9, with each increase of 1 representing a 10 times increase in energy.
Wiki User
∙ 12y ago1) Analyzing the seismic waves recorded by a seismograph.
The amplitude recorded by the seismograph can be used to find the magnitude of the earthquake.
The depth of the earthquake faulting is can give you the distance from the focus to the epicenter and how far the earthquake occurred from the fault boundary.
Finding when the earthquake occurred gives you...when the earthquake occurred =P
Comparing the speed of P-waves and S-waves can be used to determine how far the epicenter is from where you currently are.
Wiki User
∙ 15y agomagnitude is determined by the estimate of the total amount of energy released during fault ruptures
Wiki User
∙ 6y agomagnitude is measured by seismographs
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What it measured on the Richter scale?
Richter scale measures the magnitude of earthquakes.
Which is not a factor in calculating the moment magnitude of an earthquake?
magnitude of past earthquakes in the area
What caused the ground to shake so strongly and how is shaking recorded in christchurch?
Ground shaking is caused by an earthquake which is two tectonic plates that rub against eachother or overlap The magnitude of most earthquakes is measured on a ricture scale the magnitude is calculated by the ampline.
What is the relationship between intensity and magnitude of an and earthquake?
the relationship between earthquakes magnitude is the size or amount of energy an earthquake produces and has no connection to hour often earthquakes occur.
What is the highest magnitude in history of earthquakes?
The highest magnitude earthquake was a 9.5 in Chile on May 22, 1960.
What are high magnitude earthquakes?
earthquakes with high magnitude.
Why are there fewer magnitude 2 and 3 earthquakes instead of magnitude 4 earthquakes?
There are far more magnitude 2 or 3 earthquakes than magnitude 4 earthquakes. The small quakes just don't get noticed as much because they typically do little or no serious damage.
What does magnitude have to do with earthquakes?
The word magnitude (in the context of earthquakes) is used to describe the amount of energy released when one occurs.
How high can an earthquake's magnitude go?
An earthquake's magnitude can go as high as 10 or above on the Richter scale. Magnitude 10 earthquakes are extremely rare and are considered to be the strongest earthquakes ever recorded. The majority of earthquakes are of lower magnitude, with the average being around magnitude 4.
Do all earthquakes have after shock?
No only middle and big magnitude earthquakes do.
How is an earthquakes energy measured?
Magnitude
How is the moment magnitude used to describe earthquakes?
The moment magnitude scale can be used to rate earthquakes of all sizes, near or far.
How may earthquakes of 6 or more magnitude occur each year?
There's about 140 earthquakes with 6 magnitude or above a year.
Which is a factor in calculating the moment magnitude of an earthquake?
magnitude of past earthquakes in the area
Statment between the magnitude of a earthquake and how often earthquakes of the magnitude occur?
One statement you could write is that "Earthquakes of higher magnitudes are much rarer than those of lower magnitudes". The magnitude of earthquakes is a logarithmic scale, so a magnitude of 8 is TEN TIMES more powerful than a magnitude 7. This is why earthquakes of higher magnitudes are so much rarer than those of lower magnitudes.
What is the scale a seismologist uses to measure the energy of an earthquake?
These are known as magnitude scales. The most commonly known is the Richter magnitude scale which can be calculated from the amplitude of seismic waves measured by a seismometer. However it was not designed for use with larger earthquakes (greater than magnitude 7.0) or for ones a long way from the seismometer station (greater than around 650 km). As such the moment magnitude scale was developed which is calculated from the cross sectional area of the slipped fault, the elastic properties of the rock mass around the fault and the size of the fault movement. This is harder to derive than the Richter magnitude but can be used for larger earthquakes.
How bad can an earthquake be?
The largest recorded earthquake to date, the 1960 Valdivia earthquake, was calculated to be 9.5 MW (moment magnitude scale). The scale has no boundaries, though the chance of earthquakes of increasingly greater magnitude occurring diminishes rapidly.
